Hydraulic auxiliary power unit



Jan. 25, 1966 E. J. HAYES 3,230,888

HYDRAULIC AUXILIARY POWER UNIT Filed April 5, 1964 2 Sheets-Sheet l lE-v INVENTOR. 22 20472 J7 //4 ye s Jall- 1966 E. J. HAYES HYDRAULICAUXILIARY POWER UNIT 2 Sheets-Sheet 2 Filed April 5, 1964 I INVENTOR. fwdr/ .7. flayes United States Patent 3,230,888 HYDRAULIC AUXILIARY PGWERUNIT Edward'J. Hayes, Livonia, Mich., assignor to Kelsey- Hayes Company,Detroit, Mich., a corporation of Delaware Y FiledApr. 3, 1964, Ser. No.358,145

3 Claims. (Cl. 103-49) This application is a continuation-impart of mycopending application Serial No. 100,373, filed Apr. 3,

1961, now abandoned.

This invention relates to a unit for pressurizing hydraulic fluid andtransmitting it to hydraulically operated servo. devices such ashydraulically driven turbine type devices; used to develop electricalenergy, and various othertypesof deviceshaving pistons or vanes movableunder the,.= .influence of the hydraulic force to perform some work.This recitation of various uses for the unit herein disclosed is notmeant by way of limitation of its inventive subject matter but merely asillustrative of the many uses to which such a device could be put. Forexample, the unit could be used to pump emergency supplies of oilor-fue1 to engines for relatively short periods of time. t f

Essentially, the pressurizing unit is a hydraulic fluid pump comprisinga plurality of cylinders having movable members such as pistonsthereinwhich are movable under the influence of applied or actuating gaspressure to exert force on other more dense fluids, and valve meanswhich can alternatelyarid selectively transmit actuating gas to thesemovable members or pistons while simultaneously direct-ing the hydraulicfluid output of the cylinders to the servo device. The actuating gas isdelivered to the cylinders by any of a number of devices such as solidfuel propellants which are capable of, producing relatively high gaspressures from a minimum of fuel volume, specificexamples of which areset forth below.

The importance of -this hydraulic fluid pumping unit arises from suchexemplary results as the convertion of the force developed by relativelylow density fluid to force developed by high density hydraulic fluid,the selfsufliciency-of the unit in developing its own pumping power, thecompactness of the unit and its ability to provide a continuous flow ofhigh pressure hydraulic fluid fora substantial time for emergencyauxiliary operation.

It-is, therefore, a principal object of this invention to providecompact, self-containedapparatus for effectively utilizing the forcedeveloped by a relatively low density fluid to pressurize a relativelyhigh density fluid.

Another object of the present invention is to provide fluid pressurizingapparatus operable to maintain the pressure of a hydraulic system at adesired level despite fluid losses in said hydraulic system. 1

A further object is to provide the above unit with electrical circuitmeans for automatically controlling the opera-ti'on'of the actuatingpres-sure fluid and hydraulic output fluid flow in accordance with thepower consumption of the servo device.

A further specific object of this invention is to provide a gas driven,self-sustained closed system auxiliary hydraulic fluid pumping unit witheither mechanically or electrically operable valving means forcon-trolling the gas and fluid flow to effectively provide hydraulicpower without any exterior source of power or extraneous apparatus,which hydraulic fluid may be utilized in emergency situations to operatevarious types of servo devices.

Another object is to provide apumping unit of the above type which iscapable of being started by the flow of actuating gas.

Further objects and advantages of the present inven- FIGURE 2 representsa side elevational view of the unit with certain parts broken away;

FIGURE 3 represents a cross sectional view of the unit taken along theline corresponding to 3-3 of FIG- URE 1; and

FIGURE 4 represents a schematic view of a typical electrical circuit forautomatic-ally operating the power unit.

Referring to the drawings, the power unit is generally designated as 10and comprises a top cover plate 12 and a bottom plate 14 securedtogether by a plurality of bolts 16 and compressing therebetween a pairof cylinders or chambers 18 and 20. Sealing rings 22 may be providedwhere necessary in order to make these chambers substantially fluidtight. Movable members or pistons 24 and 26 are sl-idahly mounted inchambers 18 and 20 respectively to provide in chamber 18 a servo section28 and an actuating section 30, and in chamber 20 a servo section 32 andan actuating section 34. Suitable sealing rings 36 are provided on thepistons as necessary to insure a substantially fluid seal between theservo and actuating sections. At the inner portion of the cover plate 12is provided a pair of servo fluid ports 38 and 40 serving sections 28and 32 respectively, and in the outer portions of bottom plate 14 isprovided a pair of actuating gas ports 42 and 44 serving actuatingsections 30 and 34 respectively. A servo fluid control land valve 46 issecured to the top of plate 12 for directing the flow of fluid to andfrom the servo sections and the servo unit served thereby. This valve isprovided with a bore 48 communicating through passages 50 and 52 withservo ports 38 and 40 respectively, with return flow passages 54 and 56adapted for connection to the discharge port of a servo unit, and with apassage 58 connected to the inlet or feed port of said servo unit.

A solenoid 60 provided with an armature shaft 62 urged to the left byspring 64 is secured to the cover 12. Armature 62 is provided withsealing rings 65 at each end of valve 46, and with valving ridges 66 and68 positioned on either side of passageway 58. It isobvious that as thesolenoid coil "70 is energized and the armature 62 is pulled to theright to compress spring 64, ridge 68 will cooperate with land 72 todisconnect the servo section 32 from return flow passageway 56 whileconnecting servo section 32 with passageway 58 which feeds the servodevice. Simultaneously ridge 66 will cooperate with land 74 todisconnect servo section 28 from feed passageway 58 and connect section28 with passageway 54 receiving discharge fluid from the servo device.It is obvious that upon deenergization of the coil 70 of the solenoid,spring 64 will push shaft 62 to the left to connect servo section 28 tothe servo feed passageway 58 while connecting servo section 32 to thepassageway 56 receiving discharge fluid from the servo device.

Pistons 24 and 26 are alternately urged upwardly against the hydraulicfluid in their respective servo sections 28 and 32 by means ofpressurized gas entening respectively into actuating sections 30 and 34through actuating ports 42 and 44 respectively. For the purpose ofclarification, it is mentioned here that as one piston moves up, theother moves down since the hydraulic fluid system comprising both servosections, the servo valve and the driven servo device is closed. Themotion of the pistons is controlled by an actuating fluid or gas landvalve generally designated 76 which comprises a bore '78 having a gasinlet conduit 80 and a pair of grooves 82 and 84. The shaft 62 isextended into the bore 78 and is provided with a pair of v-alving ridges86 and 88. Groove 82 is connected to actuating port 42 by a conduit 90and groove 84 is connected to actuating port 44 by conduit 92. It isseen that as solenoid 60 is energized and shaft 62 is pulled to theright, gas inlet 80 will be connected to actuating section 34 whileactuating section 30 is dumped to the atmosphere through bore 78.

With shaft 62 in the position shown in FIGURE 3 within the servo fluidand actuating fluid valves, it is seen that when pressurized gas isadmitted to conduit 80 piston 26 will move upwardly to force hydraulicfluid in servo sect-ion 32 through passage 58 to the servo device, andpiston 24 will be urged downwardly by the fluid being discharged fromthe servo device and flowing through passage 54 into the servo section28. It is thus seen then that a see-saw type of piston motion willresult.

The electrical circuit shown in FIGURE 4 controls the operation ofsolenoid 60 and thereby the flow of fluids to and from the servo andactuating sections. Since it is desirable in this device to get the mostout of the gas pressure coming into inlet 80 of the'acuating fluidvalve, the electrical circuit is constructed in such a way as todeenergize the solenoid coil 70 when piston 26 is substantially at thetop of its stroke, and to energize the coil 70 when the piston 24 is atthe top of its stroke. This is accomplished by allowing the pistonsthemselves to make and break the contacts which energize and deenergizethe solenoid coil.

The electrical circuit of FIGURE 4 with components also shown in FIGURE3, comprises a source of electrical energy such as storage battery orgenerator 94 for energizing the solenoid coil '70 adapted for connectionto the source 94 across its terminals '71 and 73. A normally open switch96 is provided with a pair of terminals 98 and 100 and a contact arm102, which terminals are supported in the cover plate 12 inside of servosection 28 and which contact arm 102 is supported in electricallyinsulating material 104 in the piston 24. It is seen that as the piston24 moves arm 102 into contact with the contacts 98 and 100, the solenoid60 will be energized. Simultaneously with the energizing of solenoid 60a reiay solenoid 106 will be energized to close a set of contacts 108and 110 by a contact arm 112 Matched to the armature 114 of the solenoid106. The connecting of contacts 108 and 110 will energize a second relaycoil 116 which will cause its armature 118 to move contact arm 120 intocontact with contacts 122 and 124. A contact arm 126 inside of servosection 32 is normally held into contact with contacts 128 and 130. Itis seen, therefore, that after piston 24 has moved contact arm 102upwardly to energize the solenoid 60 and hydraulic fluid starts flowingin the reverse direction back into servo section 28, the connectionbetween contacts 98 and 100 will be broken by the downward motion ofpiston 24. However, solenoid 60 will remain energized through theholding circuit of relay coils 106, 116 and normally closed switch 126in servo section 32. As piston 24 moves downwardly toward the end of itsstroke and servo section 28 becomes filled with hydraulic fluid, piston26 moves upwardly forcing hydraulic fluid out of section 32 until acontact breaking post 132 supported in electrically insulated material134 on the piston 26 engages contact arm 126 and breaks the electricalconnection between contacts 128 and 130. When this occurs, solenoid 60will be deenergized, shaft 62 will move to the left to reverse the flowof actuating and servo fluids and again start piston 24 on its upwardmotion and piston 26 on its downward motion. It is obvious that therapidity of up and down motion or cycling of the pistons 24 and 26 willdepend upon the resistance to flow of the hydraulic fluid from the servosections and the pressure of the actuating fluid in sections 30 and 34.

The actuating pressure fluid may be supplied by any conventional gaspressure developing means such as a solid propellant charge 136 incontainer 138 which charge may be ignited by an electric arc betweenelectrodes 139 and 140 or by a small explosive ignition charge (notshown) placed adjacent this arc. There are several types of propellantcharges which may be used such as the LFT series of solid propellantssold by Standard Oil of Indiana. It is obvious that other gas-producingmeans could be used such as those which depend upon the release ofgaseous products from the chemical reaction of separate chemicalcomponents. The use to which the unit is to be put will determine thesize and chemical nature of the gas producing charge.

During the fraction of a second which it takes the pistons to reversetheir directions of travel, it may be desirable to provide some meanssuch as accumulator 142 which stores fluid in its chamber 144 held undercompression through spring 146 or by gas trapped in chamber 147. Asfluid pressure is needed during -the aforesaid fraction of a second, thefluid in chamber 144 of the accumulator will be forced out through theport 146 which is connected into the servo device feed port 58. A vent148 is provided in the bottom of the accumulator housing to allowspring'146 to be compressed. It is obvious that many types ofconventional accumulat-ors would find utility in this regard.

The illustrated electrical circuit of FIGURE 4 is one of many diflerentarrangements which would find utility in controlling the operation ofthe solenoid 60. Persons skilled in the art could readily devise a greatnumber of circuits using various normally open and normally closedswitches as variations of the normally open and closed switches 96 and126 shown by applicant.

A pressure relief valve 150'may be provided to limit the maximum gaspressure admitted to sections 30 and 34. This valve comprises a valvedisc 152 urged against port 154 by a spring 156. Chamber 158 of thisvalve communicates continuously with the inlet conduit 80 through thevalve bore 78.

The leads 139 and 140 of the charge ignitor may be connected to anyelectrical power source such as battery 94 and to any electrical switchproperly located for actuation either manually or automatically when theauxiliary power is required; For example, if the unit were used to drivean auxiliary electrical generator, the 'leads'139 and 140 couldadvantageously be connected to a switch which would be closed uponfailure of the primary generator.

As mentioned above, the type of servo unit operated by applicantspumping device may be varied, and in FIGURE 3 a turbine 160 isschematically shown. This turbine may be provided with a fluid inlet 162for connection to the feed port 58 of the valve 46; andwith a branchedfluid discharge 164 for connection to the return ports 54 and 56 of thevalve 46. An output shaft and pulley arrangement 166 may be connectedto-''- an electrical generator, for example, to provide emergencyauxiliary electrical energy.

In the event of fluidlo-sses-in the system or mechanism pressurized bythe apparatus of the presentsystem (.such as the turbine 160), it willbe apparent that insuflicient fluid will flow into the servo sections 28and 32 on the downward strokes of their pistons 24 and 26 to completelyfill the chamber 18 and 20. When this happens the pistons 24 and 26 willnot descend completely in the chambers 18 and 20, but only enough toaccommodate the recirculating hydraulic fluid. The reason for this isthat light weight return springs 168 and 170 bear against the bottoms ofthe pistons 24 and 26 to keep them from descending in the absence ofsome force or weight hydraulic fluid. It is also believed possible toeliminate the nee-d for the springs 168' and 170 by inverting the entirestructure so that as hydraulic fluid enters the chambers 18 and 20 atthe bottom thereof,

gravity will oppose movement of the piston toward the actuatingsections. Accordingly, when each piston begins its upward pumping strokethere is no Waste or lost motion in which a piston is not actuallyworking against hydraulic fluid.

While it will be apparent that the preferred embodiment of the inventiondisclosed is well calculated to ful fill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. In a recirculating hydraulic system having a servo unit operated bypressurized hydraulic fluid, emergency hydraulic fluid pressurizingapparatus including means defining a pair of chambers, a pair ofindependently operable movable walls disposed one in each of saidchambers and dividing each chamber into servo and actuating sections,servo valve means connecting said servo sections to said servo valve andsaid servo valve to said servo unit for the selective flow of hydraulicfluid between said servo unit and said servo sections, a gas generator,2. gas valve, means connecting said actuating sections to said gas valveand said gas valve to said gas generator for the selective flow of fluidfrom said gas generator to said actuating sections, switch meansoperated by said movable walls upon the reciprocation thereof towardsaid servo sections to operate said valves, said walls being movable inone direction under the influence of gas from said generator to pumpfluid in the servo sections adjacent thereto and being movable in theopposite direction only in response to the return fiow of fluid intotheir adjacent servo sections from said servo unit.

2. The structure set forth in claim 1 including means normally biasingeach of said movable walls toward their adjacent servo sections.

3. The structure set forth in claim 1 including a spring in each of saidchambers operable to bias each of said Walls in a direction toward itsadjacent servo section.

References Cited by the Examiner UNITED STATES PATENTS 212,039 2/1879Molera et a1. 54 494,782 4/ 1893 Jewell 6054 584,620 6/1897 Battey 6054657,160 9/1900 Eads 10352 1,216,664 2/1917 Dodd 6054 1,487,946 3/1924Johnson 10352 2,366,417 1/1945 MacMillin 10349 3,046,898 7/1962 Badenochet a1. 10349 DONLEY I. STOCKING, Primary Examiner.

1. IN A RECIRCULATING HYDRAULIC SYSTEM HAVING A SERVO UNIT OPERATED BYPRESSURIZED HYDRAULIC FLUID, EMERGENCY HYDRAULIC FLUID PRESSURIZINGAPPARATUS INCLUDING MEANS DEFINING A PAIR OF CHAMBERS, A PAIR OFINDEPENDENTLY OPERABLE MOVABLE WALLS DISPOSED ONE IN EACH OF SAIDCHAMBERS AND DIVIDING EACH CHAMBER INTO SERVO AND ACTUATING SECTIONS,SERVO VALVE MEANS CONNECTING SAID SERVO SECTIONS TO SAID SERVO VALVE ANDSAID SERVO VALVE TO SAID SERVO UNIT FOR THE SELECTIVE FLOW OF HYDRAULICFLUID BETWEEN SAID SERVO UNIT AND SAID SERVO SECTIONS, A GAS GENERATOR,A GAS VALVE, MEANS CONNECTING SAID ACTUATING SECTIONS TO SAID GAS VALVEAND SAID GAS VALVE TO SAID GAS GENERATOR FOR THE SELECTIVE FLOW OF FLUIDFROM SAID GAS GENERATOR TO SAID ACTUATING SECTIONS, SWITCH MEANSOPERATED BY SAID MOVABLE WALLS UPON THE RECIPROCATION THEREOF TOWARDSAID SERVO SECTIONS TO OPERATE SAID VALVES, SAID WALLS BEING MOVABLE INONE DIRECTION UNDER THE INFLUENCE OF GAS FROM SAID GENERATOR TO PUMPFLUID IN THE SERVO SECTIONS ADJACENT THERETO AND BEING MOVABLE IN THEOPPOSITE DIRECTION ONLY IN RESPONSE TO THE RETURN FLOW OF FLUID INTOTHEIR ADJACENT SERVO SECTIONS FROM SAID SERVO UNIT.